Lithium niobate photonic crystal waveguides: Far field and near field characterisation

In this paper, we experimentally investigate photonic crystal waveguides in a X-cut lithium niobate substrate. The transmission response is measured through the ΓM direction of a triangular lattice structure and the results coincide with the theoretical predictions. In addition, a scanning near-field microscope is used in collection mode to map the optical intensity distribution inside the structure putting in evidence the guiding of the light through lines of defects. This study offers perspectives towards lithium niobate tunable photonic crystal devices.